Background/Objectives: Despite growing evidence on quantitative computed tomography (CT) analysis of coronary plaques and pericoronary adipose tissue (PCAT), their association with myocardial perfusion (MP) in patients with first acute myocardial infarction (AMI) with obstructive coronary artery disease (MICAD) and non-obstructive coronary arteries (MINOCA) remain unclear. The aim of this study was to assess the relationship between quantitative CT coronary plaque components and PCAT characteristics with MP, myocardial blood flow (MBF) and coronary flow reserve (CFR) obtained by dynamic single-photon emission computed tomography (SPECT) in patients with AMI. Methods: Patients with a first episode of AMI were included in the study. All patients underwent coronary CT angiography with quantitative assessment of plaque volume (PV) and burden (PB), as well as PCAT volume and attenuation. Dynamic SPECT was performed on cadmium–zinc–telluride gamma-camera for quantitative assessment of MP parameters, stress and rest MBF, and CFR. Results: A total of 31 patients (median age 62 [56–70] years) were analyzed, including MICAD (n = 21) and MINOCA (n = 10). MICAD patients had significantly higher total PV and PB, mainly due to non-calcified and fibrofatty components (p < 0.05), while low-attenuation (LAP) and calcified plaques (CP) did not differ between groups. PCAT volumes were higher in MICAD (p < 0.05), whereas PCAT attenuation showed no differences. Dynamic SPECT revealed lower stress MBF and CFR in MICAD (p < 0.05). Correlation analysis showed positive associations of PV and PB with MP summed stress and rest scores, except LAP or CP; PB was negatively associated with MBF. In addition, PCAT volume correlated negatively with stress and rest MBF and CFR, as well as PCAT attenuation correlated positively with stress-induced MP abnormalities. Conclusions: Patients with MICAD demonstrated a greater extent of atherosclerosis and larger PCAT volume compared with MINOCA. Moreover, PCAT volume demonstrated inverse associations with MBF and CFR, indicating a potential link between PCAT characteristics and microvascular dysfunction.

Aim. To compare standard indices of myocardial perfusion scintigraphy (MPS) and quantitative indicators of myocardial dynamic single-photon emission computed tomography (SPECT) in patients with non-obstructive coronary artery disease (NOCAD).Material and methods. The study included patients with symptoms or signs of myocardial ischemia and NOCAD (<50%). All patients underwent dynamic myocardial SPECT with assessment of standard MPS indices (summed stress score (SSS), summed rest score (SRS), summed difference score (SDS)) and quantitative indicators (stress and rest myocardial blood flow (MBF), myocardial flow reserve (MFR) and stress/rest MBF difference (ΔMBF)).Results. According to MPS, 15 (26%) patients had signs of myocardial perfusion dysfunction (SSS ≥2,0). Standard MPS indices had low values as follows: SSS 0,0 (0,0; 2,0), SRS 0,0 (0,0; 0,0), SDS 0,0 (0,0; 2,0). According to dynamic myocardial SPECT, 22 (38%) patients had a reduced MFR <2,0. Quantitative indicators were characterized by greater variability compared to the MPS data as follows: stress MBF 1,34 (1,03; 1,64) ml/min/g, rest MBF 0,58 (0,42; 0,73) ml/min/g, MFR 2,42 (1,48; 2,85), ΔMBF 0,68 (0,36; 1,09). In 7 (12%) patients, ischemic myocardial changes (SSS ≥2,0) was associated with a reduced MFR <2,0, and in 28 (48%) without signs of ischemia (SSS <2,0) the MFR was within normal values ≥2,0. However, 15 (26%) had a normal radiopharmaceutical distribution and a reduced MFR, which may indicate the initial stages of microvascular dysfunction, which did not lead to myocardial ischemia.Conclusion. The dynamic SPECT allows in ~30% of cases to identify MBF and MFR disorders in NOCAD patients with normal results of standard SFM.

Aim. To study the characteristics of the course of arterial hypertension (AH) and subclinical cardiac damage during breast cancer chemotherapy with doxorubicin.Materials and methods. The study included a total of 27 women with breast cancer (BC) and a history of controlled hypertension who were to receive chemotherapy with anthracyclines. Twelve women had stage 1 hypertension; 15 women had stage 2 hypertension. The patients received dual antihypertensive therapy according to clinical guidelines. All patients underwent echocardiography and 24-hour blood pressure monitoring at baseline, after the last course of chemotherapy, and 12 months after the end of chemotherapy. The control group included 35 women with BC without a history of AH, who also were to receive anthracycline chemotherapy.Results. A significant relationship between pre-existing AH and the development of left ventricular systolic dysfunction 12 months after the completion of chemotherapy (p = 0.01) was found. According to 24-hour blood pressure monitoring, 15 women (55.6%) showed deterioration of blood pressure control after the completion of chemotherapy, which required modification of antihypertensive therapy by adding one more drug to the treatment regimen. At 12 months after the end of chemotherapy, in 13 women, hypertension control was reached with triple antihypertensive therapy. In two women, hypertension became resistant, which required prescription of a fourcomponent antihypertensive regimen.Conclusion. Pre-existing AH plays an essential role in the development of anthracycline-induced cardiotoxicity, despite the quality of blood pressure control. Polychemotherapy with anthracyclines may deteriorate blood pressure control in patients with AH, which requires addition of antihypertensive drugs to the treatment regimen.

Introduction: Nowadays, coronary computed tomography angiography (CCTA) is a well-established method for identification of coronary artery disease (CAD) in patients with low pre-test probability. Most of these patients have non-obstructive CAD (NOCAD) and microvascular dysfunction. However, the data about the relationships between coronary plaque composition and the values of myocardial blood flow (MBF) and myocardial flow reserve (MFR) is lacking. The purpose of the study is to assess the relationships between quantitative CCTA variables and dynamic CZT SPECT in NOCAD patients.

In the interests of practical healthcare, routine classifications should be modified as rarely as possible. At the same time changes should be discarded only on sufficient grounds, for example, when there are no obvious advantages of a new classification over the existing ones or they can no longer be modified by introducing fundamental changes and amendments. In this regard, the evolution of approaches to the classification of chronic heart failure (CHF) is prominent. It becomes particularly relevant due to the fact that currently experts of the Russian Society of Cardiology (RSC) are actively discussing a new draft classification of CHF. The authors of the lecture gave a brief historical insight and reviewed the main classifications of CHF used in North America, Europe, and Russia. The new classification of CHF proposed by RSC experts, which is actually a modified classification of North American colleagues, does not have obvious advantages over the currently used CHF classification in Russia (since 2002). The latter is based on the classification by Vasilenko – Strazhesko which is familiar to domestic internists, since it has become an indispensable part of their clinical practice and has stood the test of time. In addition, its underlying principles provide the potential for its flexible modification.

Aim. To study the relationship of coronary microvascular dysfunction (CMD) with the levels of pro- and anti-inflammatory biomarkers in patients with preserved ejection fraction (LVEF) and non-obstructive coronary artery disease (CAD). Material and methods . The study included 118 patients (70 men, mean age, 62,0 [58,0; 69,0] years) with preserved LVEF (62 [59; 64] %) and non-obstructive CAD. Serum levels of N-terminal pro-brain natriuretic peptide (NT-proBNP), high-sensitivity C-reactive protein (hsCRP), interleukin-1β, 6, and 10 were assessed initially by enzyme immunoassay. Coronary flow reserve (CFR) was assessed by dynamic single photon emission computed tomography. CFR ≤2 was a CMD marker. Results. Patients were divided into groups depending on CMD presence: group 1 included patients with CMD (n=45), and group 2 was the control group and included patients without CMD (n=73). HsCRP concentrations were 1,8 times higher (p=0,011) in group 1 compared to group 2. Interleukin-6 levels did not differ significantly between groups (p=0,842), while interleukin-10 concentrations were lower by 21,7 % (p=0,048), and interleukin-1β was 2,7 times higher (p=0,046) in group 1 compared to group 2. According to ROC analysis, hsCRP concentration ≥4,8 g/l (AUC=0,655; p=0,012), and NT-proBNP ≥950,6 pg/ml (AUC=0,792; p<0,001) were identified as markers associated with CMD in patients with non-obstructive CAD, while levels of interleukin-1β, 6 and 10 showed no diagnostic significance. Multivariate regression analysis showed that diastolic dysfunction (odds ratio, 3,27; 95% confidence interval, 2,26-5,64; p<0,001) and NT-proBNP ≥950,6 pg/ml (odds ratio, 2,07; 95% confidence interval, 1,56-4,12; p=0,023) were independent factors associated with CMD. Conclusion . We established that in patients with non-obstructive CAD, the pre­sence of CMD is associated with a higher expression of pro-inflammatory markers and a decrease in the expression of an anti-inflammatory marker, which may confirm the fact that chronic inflammation is one of CMD pathogenesis links.

Aim. To evaluate the effectiveness of hardware Continuous Positive Airway Pressure therapy (CPAP therapy) and its likely predictors in patients with heart failure with preserved ejection fraction (HFpEF) associated with obstructive sleep apnea syndrome (OSAS). Materials and methods. The study involved 207 men with HFpEF and OSAS (apnea/hypopnea index 15 per hour) who did not initially have ischemic disease and other structural heart pathology. At inclusion in the study, polysomnography and echocardiography were performed with an assessment of diastolic function and global longitudinal deformation of the left ventricular myocardium, as well as a 6-minute walk test (6MWT) and the level of the brain natriuretic peptide precursor (NT-proBNP) in the blood was determined. 80 patients received hardware CPAP the rapy, 127 patients made up the control group. After 12 months, 6MWT was repeated, NT-proBNP was determined, and clinical outcomes were assessed retrospectively. Results. The CPAP group had 16% fewer hospitalizations (p=0.011 [95% confidence interval – CI 4.29]) and showed a trend towards an increase in the 6MWT distance (p=0.065). To assess the likely predictors of the effectiveness of CPAP therapy, a subgroup of “responders” was identified, characterized by an increase in the distance according to the 6MWT, a decrease in the level of NT-proBNP, and the absence of adverse clinical events during the observation period. There were significant differences between responders and non-responders in apnea/hypopnea index (p=0.01 [95% CI -10.6; -2.5]), global longitudinal deformation of the left ventricular myocardium (p=0.05 [95% CI -4.7; 0]), diastolic function E/A (p=0.02 [95% CI -0.1; 0]). Conclusion. CPAP therapy improves clinical outcomes and functional status in patients with OSAS-associated HFpEF. The predictive model built using the identified efficacy predictors can be used to develop a personalized treatment algorithm for this cohort of patients.

(1) Background: The objective of this study was to determine the optimal post-processing model for dynamic cadmium–zinc–telluride single-photon emission computed tomography (CZT-SPECT). (2) Methods: A total of 235 patients who underwent diagnostic invasive coronary angiography within three months of the SPECT and those who had coronary computed tomography angiography (CCTA) before SPECT (within 3 months) were enrolled in this study. Each SPECT study was processed to obtain global and regional stress myocardial blood flow (sMBF), rest-MBF (rMBF), myocardial flow reserve (MFR) and flow difference (FD) estimates obtained with 1-tissue-compartment (1TCM) and net retention (NR) modes, both with and without attenuation correction. (3) Results: The use of AC led to significantly higher sMBF, rMBF and DF values obtained by 1TCM compared those values derived by 1TCM with NAC; the lowest values of stress MBF and rest MBF were obtained by 1TCM_NAC. The resting flow, MFR and DF were significantly (p < 0.005) higher in the AC model than in NAC. All quantitative variables were significantly (p < 0.05) higher in NR_NAC than in the 1TC_NAC model. Finally, sMBF, rMBF and FD showed significantly (p < 0.05) higher values by using 1TMC_AC compared to NR_AC. (4) Conclusions: We suggested that 1-compartment and net retention models correctly reflect coronary microcirculation and can be used for clinical practice for evaluating quantitative myocardial perfusion by dynamic SPECT. Attenuation correction is an important step in post-processing dynamic SPECT data, which increases the consistency and diagnostic accuracy of models.

Current recommendations for the primary prevention of chemotherapy cardiotoxicity are based on stratification of the risk of cardiovascular complications before anticancer treatment is initiated. The proposed cardiotoxicity risk scores take into account the presence of existing cardiovascular diseases, but do not take into account the therapy used for these diseases. Two clinical cases of patients with tumor diseases are presented. One patient had a high risk of cardiotoxicity, but even before the detection of a tumor process, he received a β-blocker, an angiotensin receptor blocker and a statin as a treatment strategy for coronary heart disease, which are recommended for the primary prevention of cardiovascular complications of chemotherapy. In this patient, development of cardiac dysfunction during ongoing antitumor treatment was not detected. In contrast, the second patient had a low risk of cardiotoxicity and was not given cardioprotective primary prophylaxis while on chemotherapy. However, this patient developed signs of severe cardiac dysfunction. It is possible that treatment of existing cardiovascular pathology with angiotensin-converting enzyme inhibitors or angiotensin receptor blockers, β-blockers and statins significantly reduce the risk of cardiotoxicity, which must be taken into account stratifying the risk of cardiotoxicity. Accordingly, it seems necessary to further improve the scales for assessing the risk of cardiotoxicity.

Background and Aims: To study the role of autonomic regulation of cardiac activity in patients with non-obstructive coronary artery disease (CAD) depending on the presence of heart failure with preserved ejection fraction (HFpEF). Methods: Group 1 included 48 patients with newly diagnosed HFpEF, group 2-17 patients without HFpEF. Non-obstructive CAD was confirmed by computed coronary angiography. NT-proBNP concentrations were determined by ELISA. Heart rate variability was assessed by 24-hour ECG monitoring. LV function parameters were assessed using echocardiography. Results: SDANN correlated with myocardial stress in diastole (r=0.345; p=0.006), and SDNNidx correlated with cardiovascular resistance (r=0.301; r=0.045) and E/e' (r=0.256; r=0.032) (Fig.1). In group 1, SDANN values (p=0.006) were 13.1% lower than in group 2. In group 1, SDNNidx values (p=0.012) were 14.8% higher than in patients of group 2. At night, group 1 showed a decrease in rMSSD by 42.5% (p=0.007) compared with group 2. In group 1 pNN50% values were 2.6 (1.7; 11.5), and in group 2 - 14.6 (6.2; 67.5) ms (p=0.009) (Fig.2). Based on ROC analysis, SDNNidx ≤49 ms (AUS=0.768; p=0.012) and pNN50 ≤5 ms (AUS=0.777; p=0.007) were defined as threshold values associated with the presence of HFpEF in patients with non-obstructive coronary artery disease (Fig.3). Conclusions: Patients with non-obstructive CAD and HFpEF showed a decrease in parasympathetic effects on the heart at night with a parallel increase in the activity of the sympathoadrenal nervous system. SDNNidx and pNN50 values can be used as a marker for diagnosing HFpEF. Funding: Russian Science Foundation No. 22-25-20019 https://rscf.ru/project/22-25-20019/ and funds from the Administration of Tomsk Region”

Recognizing the fact that isolated left ventricular (LV) diastolic dysfunction (DD) underlies approximately 50% of all heart failure cases requires a deep understanding of its principal mechanisms so that effective diagnostic and treatment strategies can be developed. Despite abundance of knowledge about the mechanisms underlying DD, many important questions regarding the pathophysiology of diastole remain unresolved. In particular, the role of endosarcomeric cytoskeleton pathology in the deterioration of the so-called active (relaxation of the LV myocardium and the atrioventricular pressure gradient at the beginning of diastole, closely related to it in a healthy heart) and passive (myocardial stiffness) characteristics of diastole needs to be clarified. The lecture briefly discusses the complex hierarchy of DD mechanisms (from the sarcomere to the whole heart) and covers the role of the giant protein titin in the latter, which is the main determinant of intracellular stiffness. Impairment of myocardial relaxation and deterioration of its wall compliance under a wide range of pathological conditions (pressure overload, ischemia, inflammation, cardiotoxic effects, oxidative stress, etc.) underlying DD can be explained by a shift in titin expression toward its more rigid N2B isoform, hypophosphorylation by protein kinases A and G or dephosphorylation by serine / threonine phosphatase 5 of its molecule in the extensible protein segment containing a unique N2B sequence, hyperphosphorylation of PEVK regions of titin by protein kinase C, as well as inhibition of the Ca 2 +-dependent titin – actin interaction. The results of deciphering these mechanisms can become a tool for developing new approaches to targeted therapy for diastolic heart failure that currently does not have effective treatment, on the one hand, and the key to understanding the therapeutic effects of drugs already used to treat chronic heart failure with preserved LV ejection fraction, on the other hand.

Aim. To reveal the association between disorders of myocardial blood flow and reserve, according to dynamic single photon emission computed tomography (SPECT), with risk factors for cardiovascular diseases (CVD) in patients with nonobstructive coronary artery disease (CAD).Material and methods. The study included patients with suspected stable nonobstructive (<50%) CAD. Based on the survey data, anamnesis, out- and in-patient medical records, we analyzed main CVD risk factors. All patients underwent dynamic myocardial SPECT and analysis of blood lipid profile in vitro. Depending on myocardial flow reserve (MFR), two groups were formed: 1. With reduced MFR <2,0 (rMFR); 2. With normal MFR ≥2,0 (nMFR).Results. The study included 47 patients divided into 2 following groups: the rMFR group consisted of 24 patients (15 men, age 56,3±9,1 years), the nMFR group — 23 patients (13 men, age 58,4±10,7 years). There was no significant difference in prevalence of CVD risk factors in groups. However, dyslipidemia was detected more often in rMFR patients (p=0,053): 58% vs 30%, respectively. In patients with rMFR, there were significantly higher levels of total cholesterol (TC) and low-density lipoprotein cholesterol (LDL-C). Correlation analysis revealed significant negative inverse relationships between MFR values with TC (ρ=-0,36, p=0,01) and LDL-C (ρ=-0,38, p=0,009). According to univariate logistic regression, significant predictors of reduced MFR were TC (odds ratio (OR), 2,32; 95% confidence interval (CI), 1,17-4,59; p=0,01) and LDL-C (OR, 2,16; 95% CI, 1,04-4,51; p=0,04). According to a stepwise multivariate logistic regression analysis, only TC was an independent predictor of a decrease in MFR (OR, 2,32; 95% CI, 1,17-4,59; p=0,02).Conclusion. MFR, determined by dynamic SPECT, is associated with TC and LDL-C levels. TC level is an independent predictor of a decrease in MFR.

Highlights Repeated hospitalizations occupy a special place in adverse clinical events in heart failure, currently representing one of the most powerful predictors of adverse outcomes in this group of patients. Echocardiographic parameters such as longitudinal myocardial deformation, displacement in the annulus of the tricuspid valve, and left atrial volume index can serve as predictors of hospitalization for cardiovascular diseases in patients with heart failure with preserved ejection fraction and obstructive sleep apnea. Abstract Aim . To study the prognostic role of individual echocardiographic parameters in heart failure with preserved ejection fraction (HFpEF) in patients with arterial hypertension and obstructive sleep apnea (OSA). Methods. The study included 59 men with hypertension and OSA (apnea/hypopnea index >15 per hour). At baseline all patients underwent a sleep study and echocardiography with an additional assessment of the global longitudinal strain (GLS). Upon inclusion in the study and after 12 months of follow-up, a 6-minute walk test was performed. After 12 months, the clinical course of the disease was retrospectively assessed. The criteria for an adverse clinical course were episodes of hospitalization for cardiovascular diseases, the development of paroxysmal atrial fibrillation or high-grade ventricular arrhythmias (III–V class according to Ryan), worsening of heart failure with a transition to a higher functional class according to NYHA. Results. Significant differences were found in several echocardiographic parameters between the groups of patients with and without hospitalizations within 12 months of follow-up: tricuspid annular plane systolic excursion (TAPSE) (p = 0.017), GLS (p = 0.005), left atrial volume index (LAVI) (p = 0.032). According to the regression analysis results, TAPSE, GLS and left ventricular ejection fraction make a statistically significant contribution to the probability of hospitalizations among the evaluated echocardiographic predictors. Conclusion. The results of the study allow us to consider certain echocardiographic parameters, in particular GLS, TAPSE and LAVI, as predictors of hospitalizations in patients with HFpEF and OSA.

Aim. To assess the development of adverse cardiovascular events in patients with non-obstructive coronary artery disease (CAD) and coronary microvascular dysfunction (CMD), identified by dynamic myocardial single-photon emission computed tomography (SPECT), during 12-month follow-up compared with patients without CMD.Material and methods. The study included 118 patients (70 men, mean age, 62,0 [58,0; 69,0] years) with preserved ejection fraction (62 [59; 64] %) and non-obstructive CAD. Serum levels of the N-terminal pro-brain natriuretic peptide were assessed at baseline by enzyme immunoassay. Coronary flow reserve (CFR) was assessed by dynamic SPECT. CFR ≤2 was a CMD marker.Results. Six patients discontinued participation in the study due to loss of contact with them, while the rest were divided into groups depending on CMD presence: group 1 included patients with CMD (CFR ≤2; n=42), and group 2 was the control group and included patients without CMD (CFR >2; n=70). Within 12-month follow-up, 25 patients reported adverse events. According to Kaplan-Meier analysis, the prevalence of adverse cardiovascular events was higher in patients with CMD (45,2%, n=19) than in patients without it (8,6%, n=6) (p<0,001). Multivariate regression analysis showed that the presence of CMD (odds ratio (OR), 2,42; 95% confidence interval (CI), 1,26-5,85; p<0,001) and diastolic dysfunction (OR, 3,27; 95% CI, 2,26-5,64; p<0,001) were independent predictors of poor outcomes. The combination of CMD with diastolic dysfunction more than 5 times increased the risk of adverse events (OR, 5,18; 95% CI, 3,61-11,84; p<0,001).Conclusion. We found that in patients with non-obstructive CAD, the presence of CMD, identified by dynamic myocardial SPECT, was associated with a higher risk of adverse cardiovascular events within 12-month follow-up period than in patients without CMD. At the same time, the combination of CMD with diastolic dysfunction more than 5 times increased the risk of adverse outcomes.

To assess the association of serum tetranectin levels with cardiac remodeling parameters and to evaluate its prognostic role in women with anthracycline-related cardiac dysfunction (ARCD) and without previous cardiovascular diseases (CVD) during 24-month follow-up period. A total of 362 women with primary diagnosed breast cancer who were planned to be treated with anthracyclines were examined. At 12 months after chemotherapy completion, all women were examined and ARCD was diagnosed in 114 patients. After 24 months of follow-up, all patients with ARCD were divided into 2 groups: group 1 comprised women with the adverse course of ARCD (n = 54), group 2 comprised those without it (n = 60). In group 1, the levels of tetranectin were lower than group 2 by 27.6

(1) Background: The results of the international studies support the assumption that coronary microvascular dysfunction (CMD) occurs significantly more often than previously identified and is associated with adverse outcomes. However, there is a lack of the accurate comprehension of its pathophysiology. The objectives of this study were to evaluate the clinical and instrumental features of CMD and to assess its prognostic value during 12 months of follow-up period. (2) Methods: A total of 118 patients with non-obstructive coronary artery disease (CAD) and preserved LV ejection fraction (62 [59; 64]%) were enrolled in the study. Serum levels of biomarkers were analyzed by enzyme-linked immunoassay. CMD was defined as the reduced myocardial flow reserve (MFR) ≤ 2 obtained by dynamic CZT-SPECT. Two-dimensional transthoracic echocardiography with evaluation of LV diastolic dysfunction was performed baseline. (3) Results: Patients were divided into groups depending on the presence of CMD: CMD+ group (MFR ≤ 2; n = 45), and CMD− group (MFR > 2; n = 73). In CMD+ group, the severity of diastolic dysfunction, the levels of biomarkers of fibrosis and inflammation were higher than in CMD− group. Multivariate regression analysis showed that the presence of diastolic dysfunction (OR 3.27; 95% CI 2.26–5.64; p < 0.001), the hyperexpression of NT-proBNP ≥ 760.5 pg/mL (OR 1.67; 95% CI 1.12–4.15; p = 0.021) and soluble ST2 ≥ 31.4 ng/mL (OR 1.37; 95% 1.08–2.98; p = 0.015) were independent factors associated with CMD. Kaplan–Meier analysis showed that a rate of the adverse outcomes was significantly (p < 0.001) higher in patients with CMD (45.2%, n = 19) than in patients without it (8.6%, n = 6). (4) Conclusions: Our data suggest that the presence of CMD was associated with the severe diastolic dysfunction and hyperexpression of the biomarkers of fibrosis and inflammation. Patients with CMD had higher rate of the adverse outcomes than those without it.

Aim . To evaluate the role of heart rate variability in the pathogenesis of chronic heart failure with preserved ejection fraction (HFpEF) in patients with non-obstructive coronary artery disease (CAD). Materials and methods . The cross-sectional study included 65 patients (55.4% were males) with non-obstructive CAD. Non-obstructive CAD (stenosis < 50%) was confirmed by coronary computed tomography angiography. Heart rate variability (HRV) was evaluated by 24-hour Holter monitoring; parameters of time series and spectral analysis were analyzed. Results . Depending on the presence of HFpEF, the patients were divided into 2 groups: group 1 (n = 48) included patients with HFpEF, and group 2 (n = 17) encompassed patients without it. In patients with HFpEF, a statistically significant decrease in the total HRV and parasympathetic effects on the heart rate, mainly at night, as well as increased activity of cerebral ergotropic systems were revealed. In group 1, the values of the time series analysis of HRV and QT dispersion based on the study of RR interval duration (SDANN and SDNNidx) had a significant direct relationship with the level of myocardial stress in diastole, the value of vascular resistance, and the E / e’ ratio. The cut-off values of SDNNidx and pNN50 were identified, that may be used as markers for early diagnosis of HFpEF. Conclusion . In patients with non-obstructive CAD and HFpEF, it is advisable to perform 24-hour Holter monitoring and assess HRV parameters by the time series analysis, which, compared with the spectral analysis, has a closer relationship with the characteristics of left ventricular diastolic function and afterload.